Question

Tolong dijawab plus dg cara penyelesaiannya ya..please?? aku sangat butuh..

trimks banyak

Answer 1

A)
a = 2
b = 4-2 = 2

Un = 100
a+(n-1).b = 100
2+(n-2).2= 100
2+2n-4 = 100
2n-2 = 100
2n = 100+2
2n = 102
n = 102/2
n = 51
maka,
Sn = n/2 . (2a+(n-1).b)

S51
= 51/2 . (2.2+(51-1).2)
= 51/2 . (4+50.2)
= 51/2 . (4+100)
= 51/2 . 104
= 51 . 52
= 2652